Patentable/Patents/US-9659776
US-9659776

Doping for FinFET

PublishedMay 23, 2017
Assigneenot available in USPTO data we have
Inventorsnot available in USPTO data we have
Technical Abstract

First and second fins are formed extending from a substrate. A first layer is formed over the first fin. The first layer comprises a first dopant. A portion of the first layer is removed from a tip portion of the first fin. A second layer is formed over the second fin. The second layer comprises a second dopant. One of the first and second dopants is a p-type dopant, and the other of the first and second dopants is an n-type dopant. A portion of the second layer is removed from a tip portion of the second fin. A solid phase diffusion process is performed to diffuse the first dopant into a non-tip portion of the first fin, and to diffuse the second dopant into a non-tip portion of the second fin.

Patent Claims
20 claims

Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.

Claim 1

Original Legal Text

1. A method, comprising: forming first and second fins extending from a substrate; forming a first layer over the first fin, wherein the first layer comprises a first dopant; removing a portion of the first layer from a tip portion of the first fin; forming a second layer over the second fin, wherein the second layer comprises a second dopant, wherein one of the first and second dopants is a p-type dopant and the other of the first and second dopants is an n-type dopant; removing a portion of the second layer from a tip portion of the second fin; and performing a solid phase diffusion process to: diffuse the first dopant into a non-tip portion of the first fin; and diffuse the second dopant into a non-tip portion of the second fin.

Plain English Translation

A method for manufacturing FinFET transistors involves creating two fins (first and second) that extend from a substrate. A layer containing a first dopant is formed on top of the first fin, and a portion of this layer is removed from the fin's tip. Similarly, a layer containing a second dopant (opposite type, either p-type or n-type, compared to the first dopant) is formed on the second fin, and a portion of this layer is also removed from the fin's tip. Finally, a solid-phase diffusion process is used to drive the first dopant into the remaining (non-tip) portion of the first fin and the second dopant into the remaining portion of the second fin, creating doped regions within the fins.

Claim 2

Original Legal Text

2. The method of claim 1 , wherein performing the solid phase diffusion process comprises annealing to diffuse the first and second dopants into the non-tip portions of the first and second fins, respectively.

Plain English Translation

The method described in the FinFET manufacturing process, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, utilizes an annealing process to drive dopants into the base of the fins, and specifically performs the solid phase diffusion process by annealing to diffuse the first and second dopants into the non-tip portions of the first and second fins, respectively. This annealing step activates and diffuses the dopants.

Claim 3

Original Legal Text

3. The method of claim 1 , wherein performing the solid phase diffusion process comprises: performing a first anneal to diffuse the first dopant into the non-tip portion of the first fin; and performing a second anneal to diffuse the second dopant into the non-tip portion of the second fin.

Plain English Translation

The FinFET manufacturing method, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, utilizes solid phase diffusion to drive the dopants into the base of the fins, and performs the solid phase diffusion process using two separate anneals: a first anneal specifically diffuses the first dopant into the non-tip portion of the first fin, followed by a second, separate anneal to diffuse the second dopant into the non-tip portion of the second fin.

Claim 4

Original Legal Text

4. The method of claim 1 , wherein the first layer comprises phosphosilicate glass and the second layer comprises borosilicate glass.

Plain English Translation

The FinFET manufacturing method, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, drives the dopants into the base of the fins, wherein the first layer formed over the first fin is made of phosphosilicate glass (PSG), and the second layer formed over the second fin is made of borosilicate glass (BSG). PSG provides a source for phosphorous (n-type dopant), and BSG provides a source for boron (p-type dopant).

Claim 5

Original Legal Text

5. The method of claim 1 , wherein the tip portions of the first and second fins are vertically separated from the non-tip portions of the first and second fins, respectively.

Plain English Translation

The FinFET manufacturing method, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, driving the dopants into the base of the fins, is characterized in that the tip portions of the first and second fins are vertically separated from the non-tip portions of the first and second fins, respectively. This vertical separation could be achieved through etching or other fabrication techniques, resulting in a recessed tip relative to the fin body.

Claim 6

Original Legal Text

6. The method of claim 1 further comprising: forming a dielectric layer of a top surface of the first and second fins; and forming an etch stop layer over the dielectric layer.

Plain English Translation

The FinFET manufacturing method, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, driving the dopants into the base of the fins, further includes forming a dielectric layer on top of the first and second fins to insulate them. An etch stop layer is then deposited over this dielectric layer, acting as a protective barrier during subsequent etching processes and preventing damage to the fins or underlying structures.

Claim 7

Original Legal Text

7. The method of claim 1 further comprising forming a spacer between the first and second fins, the spacer extending from the substrate.

Plain English Translation

The FinFET manufacturing method, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, driving the dopants into the base of the fins, further includes the creation of a spacer structure positioned between the first and second fins, extending upwards from the substrate. This spacer electrically isolates the two fins.

Claim 8

Original Legal Text

8. The method of claim 1 further comprising forming a gap between the first layer and the second layer.

Plain English Translation

The FinFET manufacturing method, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, driving the dopants into the base of the fins, includes the step of forming a physical gap between the first dopant layer on the first fin and the second dopant layer on the second fin. This gap helps to prevent unintended dopant diffusion or electrical interaction between the two dopant layers.

Claim 9

Original Legal Text

9. The method of claim 1 , wherein the tip portions of the first fin and the second fin have a length of between about 25 nanometers and 50 nanometers.

Plain English Translation

The FinFET manufacturing method, which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin and removing it from the tip, forming a second dopant layer of opposite type on the second fin and removing it from the tip, driving the dopants into the base of the fins, is characterized in that the tip portions of the first fin and the second fin, where the dopant layers are removed, have a length measuring between approximately 25 nanometers and 50 nanometers. This defines the extent of the undoped region at the fin tips.

Claim 10

Original Legal Text

10. A method, comprising: forming first and second fins extending from a substrate; forming a first dopant layer over the first fin; forming a second dopant layer over the second fin, wherein one of the first and second dopant layers includes a p-type dopant and the other of the first and second dopant layers includes an n-type dopant; removing the first dopant layer from a tip portion of the first fin; removing the second dopant layer from a tip portion of the second fin; and performing an annealing process to diffuse dopants from the first dopant layer into a base portion of the first fin and to diffuse dopants from the second dopant layer into a base portion of the second fin.

Plain English Translation

A method for manufacturing FinFET transistors involves creating two fins (first and second) that extend from a substrate. A first dopant layer is formed on the first fin, and a second dopant layer (opposite type, either p-type or n-type, compared to the first dopant) is formed on the second fin. The first dopant layer is removed from the fin's tip, and the second dopant layer is also removed from the fin's tip. Finally, an annealing process is used to diffuse the dopants from the first dopant layer into the remaining (base) portion of the first fin and the dopants from the second dopant layer into the remaining portion of the second fin, creating doped regions within the fins.

Claim 11

Original Legal Text

11. The method of claim 10 , wherein the tip portions of the first fin and the second fin have a length of between about 25 nanometers and 50 nanometers.

Plain English Translation

The method described in the FinFET manufacturing process which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin, forming a second dopant layer of opposite type on the second fin, removing the first and second dopant layers from the fin tips and annealing the structure to drive dopants into the base of the fins, is characterized in that the tip portions of the first fin and the second fin, where the dopant layers are removed, have a length measuring between approximately 25 nanometers and 50 nanometers. This defines the extent of the undoped region at the fin tips.

Claim 12

Original Legal Text

12. The method of claim 10 further comprising forming a gap between the first and second dopant layers.

Plain English Translation

The method described in the FinFET manufacturing process which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin, forming a second dopant layer of opposite type on the second fin, removing the first and second dopant layers from the fin tips and annealing the structure to drive dopants into the base of the fins, includes the step of forming a physical gap between the first dopant layer on the first fin and the second dopant layer on the second fin. This gap helps to prevent unintended dopant diffusion or electrical interaction between the two dopant layers.

Claim 13

Original Legal Text

13. The method of claim 10 further comprising forming a gate oxide layer over the tip portions of the first and second fins.

Plain English Translation

The method described in the FinFET manufacturing process which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin, forming a second dopant layer of opposite type on the second fin, removing the first and second dopant layers from the fin tips and annealing the structure to drive dopants into the base of the fins, further includes forming a gate oxide layer that covers the tip portions of both the first and second fins. This gate oxide layer insulates the fins from the gate electrode.

Claim 14

Original Legal Text

14. The method of claim 10 , wherein the tip portions of the first and second fins are vertically separated from the base portions of the first and second fins, respectively.

Plain English Translation

The method described in the FinFET manufacturing process which involves creating two fins extending from a substrate, forming a first dopant layer on the first fin, forming a second dopant layer of opposite type on the second fin, removing the first and second dopant layers from the fin tips and annealing the structure to drive dopants into the base of the fins, is characterized in that the tip portions of the first and second fins are vertically separated from the base portions of the first and second fins, respectively. This vertical separation could be achieved through etching or other fabrication techniques, resulting in a recessed tip relative to the fin body.

Claim 15

Original Legal Text

15. A method, comprising: forming first and second fins extending from a substrate, the first and second fins having a base portion and a tip portion; forming a first dopant over the first fin; forming a second dopant over the second fin, the second dopant being a different dopant type than the first dopant; removing the first dopant from the tip portion of the first fin; removing the second dopant from the tip portion of the second fin; and diffusing the first dopant into the base portion of the first fin and diffusing the second dopant into the base portion of the second fin.

Plain English Translation

A method for manufacturing FinFET transistors involves creating two fins (first and second) that extend from a substrate, each having a base and a tip. A first dopant is formed over the first fin, and a second dopant (opposite type, either p-type or n-type, compared to the first dopant) is formed over the second fin. The first dopant is removed from the fin's tip, and the second dopant is also removed from the fin's tip. Finally, the first dopant is diffused into the remaining (base) portion of the first fin, and the second dopant is diffused into the remaining portion of the second fin, creating doped regions within the fins.

Claim 16

Original Legal Text

16. The method of claim 15 , wherein the step of diffusing the first and second dopants includes performing a solid phase diffusion process, the solid phase diffusion process comprises: performing a first anneal to diffuse the first dopant into the base portion of the first fin; and performing a second anneal to diffuse the second dopant into the base portion of the second fin.

Plain English Translation

The method described in the FinFET manufacturing process involving creating two fins extending from a substrate, forming a first dopant on the first fin, forming a second dopant of opposite type on the second fin, removing the first and second dopants from the fin tips and diffusing the dopants into the base of the fins, uses a solid-phase diffusion process, and performs the solid phase diffusion process using two separate anneals: a first anneal specifically diffuses the first dopant into the base portion of the first fin, followed by a second, separate anneal to diffuse the second dopant into the base portion of the second fin.

Claim 17

Original Legal Text

17. The method of claim 15 , wherein the first dopant has a first concentration profile and the second dopant has a second concentration profile different from the first concentration profile.

Plain English Translation

The method described in the FinFET manufacturing process involving creating two fins extending from a substrate, forming a first dopant on the first fin, forming a second dopant of opposite type on the second fin, removing the first and second dopants from the fin tips and diffusing the dopants into the base of the fins, creates a first dopant with a specific concentration profile (how the concentration changes across the fin) that is different from the concentration profile of the second dopant. This difference allows for fine-tuning the electrical characteristics of the FinFET.

Claim 18

Original Legal Text

18. The method of claim 15 further comprising forming a spacer between the first and second fins, the spacer extending from the substrate.

Plain English Translation

The method described in the FinFET manufacturing process involving creating two fins extending from a substrate, forming a first dopant on the first fin, forming a second dopant of opposite type on the second fin, removing the first and second dopants from the fin tips and diffusing the dopants into the base of the fins, further includes the creation of a spacer structure positioned between the first and second fins, extending upwards from the substrate. This spacer electrically isolates the two fins.

Claim 19

Original Legal Text

19. The method of claim 15 further comprising forming a gate oxide layer over the tip portions of the first and second fins.

Plain English Translation

The method described in the FinFET manufacturing process involving creating two fins extending from a substrate, forming a first dopant on the first fin, forming a second dopant of opposite type on the second fin, removing the first and second dopants from the fin tips and diffusing the dopants into the base of the fins, further includes forming a gate oxide layer that covers the tip portions of both the first and second fins. This gate oxide layer insulates the fins from the gate electrode.

Claim 20

Original Legal Text

20. The method of claim 15 , wherein the tip portions of the first fin and the second fin have a length of between about 25 nanometers and 50 nanometers.

Plain English Translation

The method described in the FinFET manufacturing process involving creating two fins extending from a substrate, forming a first dopant on the first fin, forming a second dopant of opposite type on the second fin, removing the first and second dopants from the fin tips and diffusing the dopants into the base of the fins, is characterized in that the tip portions of the first fin and the second fin, where the dopants are removed, have a length measuring between approximately 25 nanometers and 50 nanometers. This defines the extent of the undoped region at the fin tips.

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Patent Metadata

Filing Date

May 12, 2016

Publication Date

May 23, 2017

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